Related Experiment Video
Updated: Aug 4, 2025
10:35
Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials
Published on: September 26, 2014
12.4K
Transverse Hypercrystals Formed by Periodically Modulated Phonon Polaritons.
Hanan Herzig Sheinfux1, Minwoo Jung2, Lorenzo Orsini1
1ICFO-Institut de Ciencies Fotoniques, 08860 Castelldefels, Barcelona, Spain.
ACS Nano
|April 3, 2023
Summary
Researchers created novel hypercrystals, enabling direct measurement of their unique light-manipulating properties. This breakthrough offers new insights into nanoscale light-matter interactions and optical density control.
Area of Science:
- Nanophotonics
- Metamaterials
- Solid-state physics
Background:
- Photonic crystals and metamaterials offer distinct ways to control light.
- Hypercrystals merge these concepts, exhibiting hyperbolic dispersion with periodic modulation.
- Experimental realization of hypercrystals has been challenging due to design and technical limitations.
Purpose of the Study:
- To experimentally realize hypercrystals with nanoscale lattice constants.
- To directly measure the Bloch modes and their dispersion.
- To investigate the unique spectral features and bandstructure of hypercrystals.
Main Methods:
- Fabrication of hypercrystals with lattice constants from 25 to 160 nm.
- Direct measurement of Bloch modes using scattering near-field microscopy.
- Extraction of Bloch mode dispersion from frequency-dependent measurements.
Main Results:
- Successful creation of nanoscale hypercrystals.
- Direct observation of Bloch modes and their dispersion.
- Demonstrated a switch from positive to negative group velocity.
- Observed sharp density of states peaks, indicative of intermodal coupling.
- Experimental results align with theoretical predictions of complex hypercrystal bandstructures.
Conclusions:
- This work provides the first experimental realization and characterization of nanoscale hypercrystals.
- The findings confirm the unique optical properties predicted for hypercrystals, including tunable group velocity.
- The observed spectral features offer new avenues for manipulating light-matter interactions and optical density at the nanoscale.
Related Concept Videos
02:18X-ray Crystallography
24.0K
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
24.0K
02:58Crystal Field Theory - Octahedral Complexes
26.9K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.9K
02:42Ionic Crystal Structures
14.5K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
14.5K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
43.4K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
43.4K
01:28Standing Waves in a Cavity
971
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
971
02:22Structures of Solids
14.3K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
14.3K